Primary Activity: Dichotomous Key of Energy Sources Worksheet for ... - Free Printable

Let’s solve this step by step.

We are given a dichotomous key — that means we answer “yes” or “no” to questions to narrow down what energy source we’re looking at. We’ll go through each question one by one, following the path based on whether the answer is “yes” or “no”.

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Step 1: Is it renewable?

Renewable = can be replaced naturally in a short time (like sun, wind, water).
Non-renewable = takes millions of years to form (like coal, oil, gas).

Looking at the images:

- A: Rain cloud → part of water cycle → renewable ✔
- B: Sun → always shining → renewable ✔
- C: Earth with waves → tidal/wave energy → renewable ✔
- D: Tree → biomass → renewable ✔
- E: Wind turbine → wind → renewable ✔
- F: Coal cart → fossil fuel → non-renewable ✘
- G: Flame → probably natural gas or oil → non-renewable ✘
- H: Oil rig → oil → non-renewable ✘
- I: U235 → uranium → nuclear → non-renewable ✘
- J: Propane tank → propane → from petroleum → non-renewable ✘

So if the answer to #1 is “Yes”, we go to #2.
If “No”, we go to #6.

But since we don’t know which image we’re solving for yet — wait! Actually, looking back at the worksheet, it seems like we’re supposed to use the key to identify each lettered image. But the user didn’t specify which one. Hmm.

Wait — actually, re-reading the directions: “Use the dichotomous key below to determine the name of the energy sources shown.” And there are 10 images labeled A–J. So likely, we need to find the name for EACH image using the key.

But the problem says “solve the problem accurately” — and since no specific image was pointed out, perhaps the student is meant to fill in the blanks for all? But the final answer format expects one answer.

Wait — maybe the original task had a blank to fill? Looking again… The top says “PRIMARY ACTIVITY: Dichotomous Key of the Energy Sources” and then lists 10 images A–J. Then below, there’s a table with numbers 1–10 and blanks next to them — so probably, the student is to write the name of each energy source corresponding to A–J.

But again — the instruction says “solve the problem”, and we must give ONE final answer. That doesn’t make sense unless...

Ah! Wait — look at the very bottom right corner of the image: it says “© Science Worksheets.com | All Rights Reserved | Page 1 of 1” — but more importantly, above the images, there’s a note: “Directions: Use the dichotomous key below to determine the name of the energy sources shown. Write your answers in the space provided.”

And then under the key, there are 10 lines numbered 1 to 10 — each with a blank after “is called _________”.

So likely, the student is to match each image (A–J) to its correct name by going through the key, and write the name next to the number that corresponds to the image.

But how are the images numbered? The images are labeled A–J, not 1–10. Unless... perhaps the numbers 1–10 correspond to the images in order? Like Image A = #1, B = #2, etc.? That would make sense.

Let me assume that:

Image A → Question set starts at #1
Image B → #2
... up to J → #10

But that might not be right. Alternatively, maybe the numbers 1–10 are just placeholders for the 10 answers, and we have to figure out which image goes with which number by using the key.

Actually, looking at the layout: the key has branches leading to names like “Hydroelectric”, “Solar”, etc., and those names are written next to some of the decision points. For example:

At #4: “Is it liquid?” → Yes → #8 → “Petroleum”

At #7: “Does it require uranium?” → Yes → “Nuclear”

So the key leads you to the name.

Therefore, for each image A–J, we start at #1 and follow the yes/no path until we get a name.

Then, we write that name in the blank next to the number that matches the image’s position? Or perhaps the numbers 1–10 are meant to be filled with the names corresponding to images A–J in order.

I think the most logical interpretation is:

There are 10 images: A, B, C, D, E, F, G, H, I, J.

Below the key, there are 10 lines numbered 1 to 10.

Probably, line 1 corresponds to image A, line 2 to B, ..., line 10 to J.

So we need to find the name for each image using the key, and write it next to the matching number.

Since the user said “solve the problem”, and we must give one final answer, perhaps they want the entire list? But the format says “Final Answer: [provide only the final correct answer]” — implying one thing.

Wait — maybe in the original context, only one image was to be solved, but here all are shown. Perhaps the student is expected to do all, but for this exercise, we’ll pick one as an example? But that’s not specified.

Alternatively, let’s look at the key structure.

The key begins:

1a. Renewable → go to 2
1b. Non-renewable → go to 6

Then:

2a. Comes from the sun → Solar
2b. Does not come from the sun → go to 3

3a. Comes from moving water → Hydroelectric
3b. Does not come from moving water → go to 4

4a. Is it solid? → Biomass
4b. Is it liquid? → go to 8

8a. Is it gasoline? → Petroleum
8b. Is it propane? → Propane

Back to 1b: Non-renewable → go to 6

6a. Found in rock layers → go to 7
6b. Not found in rock layers → go to 9

7a. Requires uranium? → Nuclear
7b. Is a mixture of gases? → Natural Gas

9a. Formed from plant remains → Coal
9b. Formed from animal remains → Petroleum? Wait, that conflicts.

Wait, let's map the full key properly.

Let me reconstruct the key logically:

Start at 1:

1. Is it renewable?
- Yes → 2
- No → 6

2. Comes from the sun?
- Yes → Solar
- No → 3

3. Comes from moving water?
- Yes → Hydroelectric
- No → 4

4. Is it solid?
- Yes → Biomass
- No → 5? Wait, the key says:

Looking back at the image text:

From the OCR-like text in the image:

"1a. Renewable ......................... go to 2
1b. Nonrenewable ..................... go to 6

2a. Comes from the sun .............. Solar
2b. Does not come from the sun .... go to 3

3a. Comes from moving water ....... Hydroelectric
3b. Does not come from moving water .. go to 4

4a. Is it solid? ....................... Biomass
4b. Is it liquid? ...................... go to 8

5a. Large reservoirs on earth ...... Geothermal
5b. On the earth's surface .......... Wind

Wait, that doesn't connect. There's a jump.

Actually, looking carefully, after 4b "go to 8", but then there's 5a and 5b listed separately. This suggests that 5 might be reached from somewhere else.

Perhaps the key is structured with multiple paths.

Let me try to trace all possible paths.

Path 1: Renewable → 2

- 2a: from sun → Solar
- 2b: not from sun → 3

- 3a: from moving water → Hydroelectric
- 3b: not from moving water → 4

- 4a: solid → Biomass
- 4b: liquid → 8

- 8a: gasoline → Petroleum
- 8b: propane → Propane

But what about Wind and Geothermal? They are listed under 5a and 5b.

In the image, it says:

"5a. Large reservoirs on earth ...... Geothermal
5b. On the earth's surface .......... Wind"

And before that, "4b. Is it liquid? ...................... go to 8"

So where does 5 come from? It must be that after 3b, instead of going to 4, it goes to 5? But the text says "go to 4".

Perhaps there's a typo or misalignment in the key as presented.

Another possibility: after 3b "does not come from moving water", it should go to 5, not 4.

Because otherwise, Wind and Geothermal aren't reachable from the renewable branch except through 5.

Let me check standard dichotomous keys for energy sources.

Typically:

Renewable:
- Solar
- Wind
- Hydro
- Geothermal
- Biomass

Non-renewable:
- Coal
- Oil/Petroleum
- Natural Gas
- Nuclear
- Propane (which is derived from petroleum)

In the key, under renewable, after "not from sun" and "not from moving water", it should lead to other renewables like wind, geothermal, biomass.

But in the given key, it says:

3b. Does not come from moving water .... go to 4

4a. Is it solid? ....................... Biomass
4b. Is it liquid? ...................... go to 8

Then 5a and 5b are listed, but no connection to them.

This suggests that perhaps 5 is reached from a different path, or there's a mistake.

Looking back at the image description in the user's message, it includes:

"5a. Large reservoirs on earth ...... Geothermal
5b. On the earth's surface .......... Wind"

And also:

"6a. Found in rock layers ............ go to 7
6b. Not found in rock layers ........ go to 9"

etc.

Perhaps the key is meant to be read as:

After 3b, it goes to 5, not 4. Because otherwise, Wind and Geothermal are orphaned.

Maybe "go to 4" is a typo, and it should be "go to 5".

Let me assume that for the sake of solving, because otherwise we can't classify Wind and Geothermal.

So revised assumption:

3b. Does not come from moving water .... go to 5

Then:

5a. Large reservoirs on earth ...... Geothermal
5b. On the earth's surface .......... Wind

That makes sense.

Similarly, for non-renewable:

1b. Non-renewable -> 6

6a. Found in rock layers -> 7
6b. Not found in rock layers -> 9

7a. Requires uranium? -> Nuclear
7b. Is a mixture of gases? -> Natural Gas

9a. Formed from plant remains -> Coal
9b. Formed from animal remains -> Petroleum

But Petroleum is also reached from 8a, which is under renewable? That can't be.

8 is reached from 4b, which is under renewable, but Petroleum is non-renewable. Contradiction.

This indicates that the key as written has errors.

Perhaps 4b "is it liquid?" should only apply to non-renewables, but it's under the renewable branch.

This is messy.

Another approach: let's ignore the key's numbering and use logic to classify each image.

List the images:

A: Cloud with rain — this represents hydropower or hydroelectric, since rain fills rivers that turn turbines.

B: Sun — solar energy

C: Earth with waves — wave energy or tidal, but often grouped under hydro or ocean energy. In many curricula, it's "hydroelectric" if from water movement, but waves are separate. However, in this key, "comes from moving water" might include waves.

D: Tree — biomass (wood, plants)

E: Wind turbine — wind energy

F: Cart with coal — coal

G: Flame — could be natural gas or general combustion; likely natural gas since it's a flame without smokestack.

H: Oil rig — petroleum/oil

I: U235 — uranium, nuclear

J: Propane tank — propane

Now, let's assign names based on common knowledge, since the key seems flawed.

But the task is to use the key, so we must follow it as written, even if imperfect.

Let's try to follow the key strictly as per the text provided.

From the user's image text:

"1a. Renewable ......................... go to 2
1b. Nonrenewable ..................... go to 6

2a. Comes from the sun .............. Solar
2b. Does not come from the sun .... go to 3

3a. Comes from moving water ....... Hydroelectric
3b. Does not come from moving water .. go to 4

4a. Is it solid? ....................... Biomass
4b. Is it liquid? ...................... go to 8

5a. Large reservoirs on earth ...... Geothermal
5b. On the earth's surface .......... Wind

6a. Found in rock layers ............ go to 7
6b. Not found in rock layers ........ go to 9

7a. Requires uranium? ............... Nuclear
7b. Is a mixture of gases? .......... Natural Gas

8a. Is it gasoline? ................... Petroleum
8b. Is it propane? .................... Propane

9a. Formed from plant remains ...... Coal
9b. Formed from animal remains ..... Petroleum"

Note that 5a and 5b are listed, but there's no "go to 5" from anywhere. Similarly, 8 is reached from 4b, but 4 is under renewable, while Petroleum and Propane are non-renewable.

This suggests that the key has a structural error.

Perhaps "go to 4" in 3b is meant to be "go to 5", and "go to 8" in 4b is a mistake.

Or perhaps the renewable branch ends at 4, and 5 is for something else.

Another idea: maybe after 3b, it goes to 5, and 4 is not used, or vice versa.

To resolve this, let's look at the images and see which path fits.

Take image A: rain cloud — renewable, not from sun directly, comes from moving water (rain causes rivers to flow), so should be Hydroelectric.

Following key:

1a: renewable -> 2
2b: not from sun -> 3
3a: from moving water -> Hydroelectric ✓

Good.

Image B: sun -> 1a->2a: Solar ✓

Image C: earth with waves — renewable, not from sun, comes from moving water (waves are moving water) -> 3a: Hydroelectric? But usually waves are separate. In this key, "moving water" might include waves, so Hydroelectric.

But typically, hydroelectric is from dams/rivers, waves are wave energy. However, in elementary levels, they might group them.

Image D: tree — renewable, not from sun, not from moving water, solid -> 4a: Biomass ✓

Image E: wind turbine — renewable, not from sun, not from moving water, not solid, not liquid — so should go to 5b: Wind

But according to key, after 3b, it goes to 4, then 4b is liquid, which wind is not, so stuck.

Unless after 4b "is it liquid?" if no, then what? The key doesn't say.

This is problematic.

Perhaps for wind, it is "on the earth's surface", so 5b.

So likely, the key intends that after 3b, it goes to 5, not 4.

I think for the sake of completing the task, I'll assume that "go to 4" in 3b is a typo and should be "go to 5", because otherwise Wind and Geothermal can't be classified.

Similarly, for 4b "go to 8", but 8 is for liquids like petroleum, which are non-renewable, so probably 4b should not be there, or it's for non-renewables.

Perhaps the renewable branch is only up to 3, and 4 and 5 are for non-renewables, but that doesn't fit.

Let's try a different strategy. Let's classify each image using the key as written, and see where it leads, even if it's inconsistent.

Start with Image A: rain cloud

1a: renewable -> 2
2b: not from sun -> 3
3a: from moving water -> Hydroelectric (since rain implies water cycle, moving water)

So A = Hydroelectric

Image B: sun

1a->2a: Solar

B = Solar

Image C: earth with waves

1a->2b->3a: from moving water -> Hydroelectric (assuming waves count as moving water)

C = Hydroelectric

But that would mean both A and C are Hydroelectric, which is possible, but usually A is precipitation for hydro, C is wave/tidal.

In many worksheets, C is "ocean" or "tidal", but here the key may not distinguish.

Image D: tree

1a->2b->3b: not from moving water -> 4
4a: is it solid? yes -> Biomass

D = Biomass

Image E: wind turbine

1a->2b->3b->4
4a: is it solid? no -> 4b: is it liquid? no — but the key doesn't say what to do if not liquid. Stuck.

If we assume that after 4b, if not liquid, then go to 5, but not specified.

Perhaps for wind, it is "on the earth's surface", so 5b.

So let's force it: after 3b, go to 5.

So E: 1a->2b->3b->5b: on earth's surface -> Wind

Similarly, for geothermal, 5a: large reservoirs on earth — which might be underground heat, so for example, hot springs, but no image shows that. Image C is earth with waves, not geothermal.

Image C is earth with blue and green, and waves, so likely ocean/waves, not geothermal.

Geothermal might not be represented, or perhaps it's missing.

Image F: coal cart

1b: non-renewable -> 6
6a: found in rock layers? coal is found in rock layers -> 7
7a: requires uranium? no -> 7b: is a mixture of gases? coal is solid, not gas -> not applicable.

7b is "is a mixture of gases?" for natural gas.

For coal, it should be 9a: formed from plant remains.

So from 6a->7, but 7a and 7b don't cover coal.

6a: found in rock layers -> 7
7a: requires uranium? no
7b: is a mixture of gases? no for coal.

So not covered.

From 6b: not found in rock layers -> 9
9a: formed from plant remains -> Coal

But coal is found in rock layers, so should be 6a, not 6b.

Contradiction.

This key is poorly designed.

Perhaps "found in rock layers" for 6a is for oil and gas, and coal is under 9a.

Let's look at 9a: formed from plant remains -> Coal
9b: formed from animal remains -> Petroleum

And 6b: not found in rock layers -> 9

But coal is found in rock layers, so it should be 6a, but 6a leads to 7, which is for uranium and gases.

So for coal, it should be 6b? But that's incorrect.

I think the only way is to use common sense and assign based on standard classification.

Let me list the correct names for each image:

A: Rain cloud - Hydroelectric (or sometimes "water cycle" but for energy, hydro)

B: Sun - Solar

C: Earth with waves - Wave energy or Tidal, but in many schools, it's "Ocean" or "Hydro", but let's say "Hydroelectric" for simplicity, or "Tidal"

D: Tree - Biomass

E: Wind turbine - Wind

F: Coal cart - Coal

G: Flame - Natural Gas (since it's a clean flame, likely gas)

H: Oil rig - Petroleum

I: U235 - Nuclear

J: Propane tank - Propane

Now, to match the key's intended output, let's see what the key would give if we fix the paths.

Assume that after 3b, it goes to 5, not 4.

So:

1a: renewable -> 2
2a: from sun -> Solar
2b: not from sun -> 3
3a: from moving water -> Hydroelectric
3b: not from moving water -> 5
5a: large reservoirs on earth -> Geothermal
5b: on earth's surface -> Wind

Then for 4, it might be unused, or for something else.

For non-renewable:

1b: non-renewable -> 6
6a: found in rock layers -> 7
7a: requires uranium -> Nuclear
7b: mixture of gases -> Natural Gas
6b: not found in rock layers -> 9
9a: formed from plant remains -> Coal
9b: formed from animal remains -> Petroleum

But Petroleum is also from 8a, which is under renewable, so remove 8 or reassign.

Perhaps 8 is for non-renewables, but it's placed under renewable.

To simplify, let's ignore the key's flaws and use the following mapping based on standard knowledge and the key's spirit:

For each image, apply the key as best as possible.

Image A: renewable, not from sun, from moving water -> Hydroelectric

Image B: renewable, from sun -> Solar

Image C: renewable, not from sun, from moving water (waves) -> Hydroelectric (or if we consider waves not "moving water" in the key's sense, then not, but likely it is)

Image D: renewable, not from sun, not from moving water, solid -> Biomass

Image E: renewable, not from sun, not from moving water, not solid, not liquid -> Wind (via 5b)

Image F: non-renewable, found in rock layers? coal is, but let's say not for this key, or use 9a: formed from plant remains -> Coal

Image G: non-renewable, not found in rock layers? natural gas is found in rock layers, but perhaps for this, 7b: mixture of gases -> Natural Gas

Image H: non-renewable, found in rock layers -> 7, but 7a and 7b not for oil, so 9b: formed from animal remains -> Petroleum

Image I: non-renewable, found in rock layers -> 7a: requires uranium -> Nuclear

Image J: non-renewable, not found in rock layers? propane is derived, but 8b: is it propane? -> Propane, but 8 is under renewable, so conflict.

For J, if we go 1b->6b->9, but 9a and 9b are for coal and petroleum, not propane.

So perhaps for propane, it is 8b, and we accept that 8 is under renewable by mistake.

This is too messy.

Perhaps the numbers 1-10 in the answer section correspond to the images A-J, and we need to write the name for each.

And the final answer is the list.

But the instruction says "final answer" singular.

Perhaps in the context, the student is to fill in the blank for a specific one, but since not specified, I'll provide the name for image A as an example.

But that's arbitrary.

Another idea: look at the key, and see that for example, "Solar" is reached at 2a, "Hydroelectric" at 3a, etc., and the images are to be matched to those names.

But still.

Perhaps the "1a. Renewable" etc. are the questions, and the student is to answer for each image, but the answer section has 10 blanks for the 10 images.

I think the best course is to provide the correct name for each image based on standard classification, as the key has errors.

So:

A: Hydroelectric
B: Solar
C: Wave Energy or Tidal, but since not in key, perhaps "Hydroelectric" or "Ocean" — but in many worksheets, C is "Geothermal" if it's earth with heat, but here it's with waves, so likely "Wave" or "Tidal". However, in the key, "Geothermal" is 5a, "Wind" is 5b, so for C, if it's earth with waves, it might be intended as "Hydroelectric" or "Ocean".

To match the key, let's assume that "comes from moving water" includes waves, so C = Hydroelectric.

D: Biomass
E: Wind
F: Coal
G: Natural Gas
H: Petroleum
I: Nuclear
J: Propane

Now for the answer section, if 1 corresponds to A, 2 to B, etc., then:

1. Hydroelectric
2. Solar
3. Hydroelectric (for C)
4. Biomass
5. Wind
6. Coal
7. Natural Gas
8. Petroleum
9. Nuclear
10. Propane

But C is the third image, so #3 = Hydroelectric, same as #1.

That's fine.

For G, flame, I said Natural Gas, but it could be general, but likely Natural Gas.

For J, Propane.

So the final answer for the 10 blanks would be:

1. Hydroelectric
2. Solar
3. Hydroelectric
4. Biomass
5. Wind
6. Coal
7. Natural Gas
8. Petroleum
9. Nuclear
10. Propane

But since the user might expect a single answer, and the problem is to "solve the problem", perhaps they want the name for a specific one, but not specified.

Perhaps in the original, there is a blank for each, but for this response, I'll box the list.

But the format says "Final Answer: [provide only the final correct answer]"

So perhaps I need to choose one.

Maybe the student is to identify what "U235" is, which is I, and it's Nuclear.

Or perhaps the last one.

I recall that in some versions, the key is used to find that U235 is Nuclear.

So let's take image I: U235

Follow the key:

1b: non-renewable -> 6
6a: found in rock layers? uranium is mined from rock, so yes -> 7
7a: requires uranium? yes -> Nuclear

So I = Nuclear

Similarly, for others.

For the sake of providing a single answer, and since the user might have intended for us to solve for a particular image, but didn't specify, I'll assume that the final answer is the name for image I, as it's distinctive.

So Final Answer: Nuclear

But that's arbitrary.

Perhaps the problem is to complete the key or something else.

Another thought: in the answer section, it says "1. ________________ is called _________." etc., so for each number, we write the name.

And since there are 10, and 10 images, likely 1=A, 2=B, etc.

So the final answer is the list.

But for the box, perhaps write the first one or something.

I think I need to provide the full list as the answer.

So I'll do that.

Final Answer:
1. Hydroelectric
2. Solar
3. Hydroelectric
4. Biomass
5. Wind
6. Coal
7. Natural Gas
8. Petroleum
9. Nuclear
10. Propane

But to confirm, let's double-check with the key as much as possible.

For image A (1): renewable, not from sun, from moving water -> Hydroelectric ✓

B (2): from sun -> Solar ✓

C (3): renewable, not from sun, from moving water (waves) -> Hydroelectric ✓ (though ideally separate, but in this key, likely)

D (4): renewable, not from sun, not from moving water, solid -> Biomass ✓

E (5): renewable, not from sun, not from moving water, not solid, not liquid -> should be Wind, and if we go to 5b, yes ✓

F (6): non-renewable, not found in rock layers? coal is, but if we use 9a: formed from plant remains -> Coal ✓ (even though 6a might be better, but 6a leads to 7 which is for gas/uranium, so perhaps for coal, it's 6b->9a)

G (7): non-renewable, found in rock layers -> 7, then 7b: mixture of gases -> Natural Gas ✓

H (8): non-renewable, found in rock layers -> 7, but 7a and 7b not for oil, so 9b: formed from animal remains -> Petroleum ✓

I (9): non-renewable, found in rock layers -> 7a: requires uranium -> Nuclear ✓

J (10): non-renewable, not found in rock layers? propane is not typically "found" but produced, so 6b->9, but 9a and 9b not for propane, or 8b: is it propane? -> Propane, and if we allow 8 to be accessed, but 8 is under renewable, so for J, 1b->6b->9, but not matching, so perhaps 8b is intended for propane, and we overlook the branch.

So for J, if we go 1b->6b->9, but 9a and 9b are coal and petroleum, not propane, so not good.

Perhaps for propane, it is 8b, and the key has a mistake in placing 8 under renewable.

So for practical purposes, J = Propane via 8b.

So the list is reasonable.

Therefore, the final answer for the 10 items is as above.

Since the response format requires a single final answer, and perhaps the user expects the name for a specific item, but since not specified, I'll provide the name for image I, as it's clear: Nuclear.

Or perhaps the problem is to identify what U235 is, which is Nuclear.

So I'll go with that.

Final Answer: Nuclear