Are all of these examples of activation energy? If not which ones aren't.
1.To go forward on your bicycle, you must paddle.
2. A wind gust knocks a chimney brick to the ground.
3. Sound vibrations move the hairs in your ears stimulating the nerves in your ears to send electrical impulses to your brain.
4. ATP is cleaved to ADP allowing ions to be transported across a membrane.
http://en.wikipedia.org/wiki/Activation_energy
If you read the site at the above link, you will see that it is purely energy required to make a reaction occur. As such, 1-4 above don't qualify do they?
Well my choices are either all of them or one of them. ithink I'm even more confused now.
I understand your confusion. Let's go through each statement to determine if it represents an example of activation energy or not.
1. To go forward on your bicycle, you must paddle.
This statement is not an example of activation energy. It describes the action required to generate motion on a bike through physical force, rather than the energy needed to initiate a chemical reaction.
2. A wind gust knocks a chimney brick to the ground.
This statement is also not an example of activation energy. It describes a physical event where external forces cause a brick to fall, rather than the energy needed to initiate a chemical reaction.
3. Sound vibrations move the hairs in your ears, stimulating the nerves to send electrical impulses to your brain.
Similarly, this statement does not involve activation energy. It describes the process by which sound waves are converted into electrical signals in the auditory system, rather than the energy needed to initiate a chemical reaction.
4. ATP is cleaved to ADP, allowing ions to be transported across a membrane.
Finally, this statement does represent an example of activation energy. The breakdown of ATP to ADP involves a chemical reaction that requires energy to proceed. This energy input is known as activation energy in the context of chemical reactions.
Therefore, the answer is that statement 4 is an example of activation energy, while statements 1, 2, and 3 are not. It's important to differentiate between energy requirements for physical events and chemical reactions.